1. Field of the Invention
The present invention relates generally to restricting access to documents on computers. More particularly, the present invention relates to a method and system for preventing unauthorized copying of content from a secured document in one application program to another application program.
2. Description of the Related Art
The Internet is the fastest growing telecommunications medium in history. The growth and the easy access it affords have significantly enhanced the opportunity to use advanced information technology for both the public and private sectors. The Internet also provides unprecedented opportunities for interaction and data sharing among businesses and individuals.
Unfortunately, however, the advantages provided by the Internet come with a significantly greater element of risk to the ownership, copyright, piracy, security and integrity of information. For example, one can easily copy an article from a web site into his own computer, and then use the unauthorized copy for his own purposes. In particular, anyone using a web browser application to view an article posted at a web site on the Internet can easily copy some or all of the article by simply highlighting the desired portion of the article, and then selecting a “copy” command made available by the web browser application. The copied text can thereafter be literally used for any purpose. Such unauthorized copying of information or content presents serious concerns for electronic publishers and others.
Furthermore, numerous proprietary and sensitive documents are created daily in a wide range of industries. Although measures may be taken to secure these documents, such as password protection or encryption, once these documents are displayed by a web browser or other application, one can normally perform a “copy” command to copy some or all of a document being displayed into a designated region in memory referred to as a buffer. In Microsoft Windows applications, the buffer is referred to as a clipboard which is provided by a clipboard application that is part of the Windows operating system. A “copy” command stores selected content to the clipboard and a “paste” command retrieves content from the clipboard. Once content has been copied to the clipboard, it remains in the clipboard until replaced by a different set of content. Hence, content in the clipboard can be repeatedly copied to as many different documents as the user desires.
One of the features of the clipboard is that it can be accessed by most application program running on the computer. As a result, the user is not limited to inserting the copied content into the same document from which it was copied from. Rather, the content stored in the clipboard can be placed within any document displayed by the computer. For example, the user can select a portion of text from a document created with a word processing application and copy it to the clipboard, switch to another text document created with the same or different word processing program, and paste it into that document from the clipboard. In the same manner, the user can copy the content from the clipboard into a non-text document, such as a drawing document created with a graphics application.
Thus, there is a need for techniques or mechanisms to control clipboard usage when content from a secured document is being copied.